I have an hmf, k&n and a dynojet jet kit in my vinson. The jetting is a 126 main and 3 turns on air mixture screw. I seems to run really well, however when i checked the plug it was really clean and silvery colored and wasn't at all brown. I called dynojet and they said that it was normal to be that color. I then called dealer and he said it should be coffee colored. I then messed around with the jetting and put in a 138 main and moved the needle up two groves and the plug still comes out silver colored. No matter how i change the jetting the plug still comes out silver. What the hell am i supposed to do ? If i burn up my engine i'm gonna be really pissed! Anyone have any suggestions?

 

u went richer on the main and leaner on the needle? id make it burn rich then step down. leave needle in middle tel u get main richer .

 

Mine is jetted with a 145 jet. That is the jet hmf sent with the muffler. I have 2 3/4 turns on the air screw. My spark plug is black. I guess I should go a litter smaller on the jet, but I'd say you are not jetted big enough. I have some more jets stached around here somewhere but I can't find them. The motorcycle shop I bought them from closed down, but they were only about $3 a piece. I was thinking about going down to a 140 or 138 1/2.

 

I had the 142 main jet that hmf sent me with the pipe in my vinson and it ran with a silver colored pulg! I then bought the dyno-jet kit with the adjustable needle and installed it just the way the directions said to( third grove on needle, 126 maine and 3 turns on mixture screw) and it still runs with a silvery colered plug! I even tried putting the stock air filter back in and it still runs the same color. The people at dyonjet said that the color of the plug is irrelevent because of all the additives in todays gas. they said it would be sliver/white no matter if it was rich or lean. Everybody else tells me it should be brown.